1. Field of the Invention
The present invention relates to printhead maintenance in an imaging apparatus, and, more particularly, to a printhead capping assembly.
2. Description of the Related Art
Ink jet printers form an image on a print medium by selectively ejecting ink from one or more of a plurality of ink jet nozzles formed in a nozzle plate of an ink jet printhead. In order to maintain the printhead at an acceptable level of performance, ink jet printers typically include a maintenance station for performing scheduled maintenance operations and for providing a sealed environment for the printhead nozzle plate during periods of non-use.
One example of a maintenance station includes a movable maintenance sled including a printhead wiper and a printhead cap. The printhead wiper includes a blade edge for engaging the printhead nozzle plate to remove waste ink and contaminants that have accumulated on the printhead nozzle plate during printing. The printhead cap is moved by the maintenance sled from a non-contact position with respect to the printhead to a contact position with respect to the printhead in an attempt to provide a sealed environment around the ink jet nozzles of the printhead.
Typically, the cap is formed as a generally rectangular structure defined by four adjoining walls that extend vertically upwardly from a base, and is made from an elastomer, with an upper portion of the four adjoining walls defining a single sealing lip. Commonly, the elastomer cap is placed over the nozzle plate of the printhead in an attempt to provide a sufficiently humid environment to avoid undesirable drying and crystallization of ink on the printhead that may plug ink jet nozzles. Such a cap attempts to form an effective seal between the printhead nozzles and the ambient environment. However, where such an effective seal is formed, such a system may not provide adequate water containment evaporation.
What is needed in the art is a printhead capping assembly designed to maintain an effective seal around the printhead nozzle plate while providing adequate water containment evaporation at a desired evaporation loss rate.
The present invention provides a printhead capping assembly designed to maintain an effective seal around the printhead nozzle plate while providing adequate water containment evaporation at a desired evaporation loss rate.
The invention, in one form thereof, relates to a printhead capping assembly. The printhead capping assembly includes a cap holder, a printhead cap and a pin. The cap holder includes a first base, with the first base having a first hole. The printhead cap is positioned adjacent to the first base. The printhead cap includes a second base, with the second base having a second hole. The pin includes a head and a shaft. The shaft has a proximal end and a distal end, with the proximal end being adjacent to the head. The head has an outer periphery, and a bottom surface extending outwardly from the shaft toward the outer periphery. The pin has a channel including a first channel portion and a second channel portion. The first channel portion is formed in the head of the pin and extends from the outer periphery of the head to the shaft. The second channel portion is formed in the shaft. The first channel portion is connected to the second channel portion. The pin is inserted through the second hole and into the first hole to place the head in contact with the second base of the printhead cap. The second base of the printhead cap seals along the first channel portion of the head of the pin to define a first vent path portion.
Such a printhead capping assembly may be included in, for example, an ink jet printer.
In another form thereof, the invention relates to a printhead capping assembly, including a cap holder, a printhead cap and a pin. The cap holder includes a first base, with the first base having a first hole. The printhead cap is positioned adjacent to the first base. The printhead cap includes a second base, with the second base having a second hole. The pin includes a head and a shaft. The shaft has a proximal end and a distal end, with the proximal end being adjacent to the head. The head has an outer periphery, and a bottom surface extending outwardly from the shaft toward the outer periphery. The pin has a channel including a serpentine channel portion formed in the bottom surface of the head. The distal end of the shaft is inserted through the second hole and into the first hole to place the head in contact with the second base. The second base of the printhead cap seals along an extent of the serpentine channel portion to define a serpentine vent path portion.
In still another form thereof, the invention relates to a device. The device includes a pin including a head and a shaft. The shaft has a proximal end and a distal end, with the proximal end being adjacent to the head. The head has an outer periphery and a bottom surface extending outwardly from the shaft toward the outer periphery. A serpentine channel is formed in the bottom surface of the head.
An advantage of the invention is the ability to establish water containment evaporation with respect to a capped printhead at a desired evaporation loss rate by selection of an appropriate vent path length to width ratio.
Another advantage of the invention is the ability to establish an appropriate vent path length in a relatively small area.